diff options
| author | Eric Dumazet <dada1@cosmosbay.com> | 2007-11-07 02:40:20 -0800 |
|---|---|---|
| committer | David S. Miller <davem@sunset.davemloft.net> | 2007-11-07 04:15:11 -0800 |
| commit | 230140cffa7feae90ad50bf259db1fa07674f3a7 (patch) | |
| tree | 815472add31606423a508a17806b7884f0ab3e2e /net/ipv4/tcp_ipv4.c | |
| parent | efac52762b1e3fe3035d29e82d8ee1aebc45e4a7 (diff) | |
[INET]: Remove per bucket rwlock in tcp/dccp ehash table.
As done two years ago on IP route cache table (commit
22c047ccbc68fa8f3fa57f0e8f906479a062c426) , we can avoid using one
lock per hash bucket for the huge TCP/DCCP hash tables.
On a typical x86_64 platform, this saves about 2MB or 4MB of ram, for
litle performance differences. (we hit a different cache line for the
rwlock, but then the bucket cache line have a better sharing factor
among cpus, since we dirty it less often). For netstat or ss commands
that want a full scan of hash table, we perform fewer memory accesses.
Using a 'small' table of hashed rwlocks should be more than enough to
provide correct SMP concurrency between different buckets, without
using too much memory. Sizing of this table depends on
num_possible_cpus() and various CONFIG settings.
This patch provides some locking abstraction that may ease a future
work using a different model for TCP/DCCP table.
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Acked-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_ipv4.c')
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index e9127cdced20..e566f3c67677 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -2049,8 +2049,9 @@ static void *established_get_first(struct seq_file *seq) struct sock *sk; struct hlist_node *node; struct inet_timewait_sock *tw; + rwlock_t *lock = inet_ehash_lockp(&tcp_hashinfo, st->bucket); - read_lock_bh(&tcp_hashinfo.ehash[st->bucket].lock); + read_lock_bh(lock); sk_for_each(sk, node, &tcp_hashinfo.ehash[st->bucket].chain) { if (sk->sk_family != st->family) { continue; @@ -2067,7 +2068,7 @@ static void *established_get_first(struct seq_file *seq) rc = tw; goto out; } - read_unlock_bh(&tcp_hashinfo.ehash[st->bucket].lock); + read_unlock_bh(lock); st->state = TCP_SEQ_STATE_ESTABLISHED; } out: @@ -2094,11 +2095,11 @@ get_tw: cur = tw; goto out; } - read_unlock_bh(&tcp_hashinfo.ehash[st->bucket].lock); + read_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket)); st->state = TCP_SEQ_STATE_ESTABLISHED; if (++st->bucket < tcp_hashinfo.ehash_size) { - read_lock_bh(&tcp_hashinfo.ehash[st->bucket].lock); + read_lock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket)); sk = sk_head(&tcp_hashinfo.ehash[st->bucket].chain); } else { cur = NULL; @@ -2206,7 +2207,7 @@ static void tcp_seq_stop(struct seq_file *seq, void *v) case TCP_SEQ_STATE_TIME_WAIT: case TCP_SEQ_STATE_ESTABLISHED: if (v) - read_unlock_bh(&tcp_hashinfo.ehash[st->bucket].lock); + read_unlock_bh(inet_ehash_lockp(&tcp_hashinfo, st->bucket)); break; } } |